Background We aimed to evaluate if vertebrobasilar anatomic variations impact reperfusion and outcome in intra-arterial therapy (IAT) for basilar artery occlusion (BAO).

Methods Consecutive BAO patients with symptom onset <24 h treated with IAT were included. Vertebral artery (VA) V3 and posterior communicating artery (PCoA) diameters were measured (CT angiography or MR angiography). The presence of PCoA atresia, VA hypoplasia, VAs that end in the posterior inferior cerebellar artery (PICA), and extracranial VA occlusion was recorded.

Results 38 BAO patients were included. Mean age was 63±15 years; 52% were men. Baseline National Institutes of Health Stroke Scale score was 21±9, and mean/median time from symptom onset to IAT were 10/7 h. First generation thrombectomy devices were mostly used. Overall Treatment in Cerebral Ischemia 2b-3 reperfusion was 68.4%. Good outcome (modified Rankin Scale score ≤2) was observed in 17.8% and mortality in 64.3% of cases at 90 days. 55% of patients had an atretic PCoA while 47% had a hypoplastic VA. The mean sum of the bilateral PCoA and VA diameters were 2.3±1.2 and 5.2±5.2 mm, respectively. VAs that end in the PICA was noted in 23% of patients, and extracranial VA occlusion in 42%. BAO was proximal/mid/distal in 36%/29%/34%. Multivariate linear regression analysis indicated hypertensive disease (β=2.97; 95% CI 1.15 to 4.79; p<0.01) and reperfusion rate (β=−0.40; 95% CI −0.74 to −0.70; p=0.02) independently associated with outcome. Multivariate analysis for predictors of reperfusion failed to identify other associations. A trend for better reperfusion with stent retrievers was noted (β=1.82; 95% CI −0.24 to 3.88; p=0.08).

Conclusions Reperfusion emerged as a predictor of good outcome in patients that underwent IAT for BAO. Angioarchitectural variations of the posterior circulation were not found to impact reperfusion or clinical outcome.